JP5176499B2 - Porous hollow fiber membrane and method for producing the same, and hollow fiber membrane module - Google Patents

Description

  The present invention relates to a porous hollow fiber membrane suitably used for the treatment of an aqueous fluid. More specifically, the present invention relates to a porous hollow fiber membrane that can be suitably used for the treatment of aqueous fluids such as water treatment, blood treatment, and the food field, a method for producing the same, and a hollow fiber membrane module.

  Conventionally, hollow fiber membranes have a hollow portion filled with an inert liquid or water or a liquid filled with hollow fiber membrane materials such as liquid paraffin and isopropyl myristate due to differences in manufacturing method and shipping form. What is not filled is known. (For example, refer to Patent Document 1).

  Further, for example, a hollow fiber membrane having an asymmetric structure made of a polysulfone-based resin and a hydrophilic material typified by polyvinyl pyrrolidone includes a bundle of hollow fiber membranes that are bundled in a state that does not substantially contain water. (For example, refer to Patent Document 2).

  In these hollow fiber membrane assemblies stored in contact with a gas or a hydrophobic liquid, the hollow fiber membrane is hydrophobized by long-term storage, and after molding into a module, it can be primed with an aqueous fluid. Immediately after that, there was a problem that sufficient performance could not be exhibited.

In cheese filled with a hydrophobic liquid such as liquid paraffin in the hollow part, it is known that the membrane wall part is filled with a hydrophilic substance such as glycerin in order to retain the membrane pores and impart hydrophilicity, Since the membrane surface on the hollow portion side is in contact with the hydrophobic liquid, it is inevitable that the membrane becomes partially hydrophobic during long-term storage.
JP-A-5-64730 JP-A-6-296686

  In view of the above prior art, the present invention provides a porous hollow fiber membrane capable of quickly exhibiting desired performance immediately after priming with an aqueous fluid, even after long-term storage and drying in a high temperature and / or low humidity environment. An object of the present invention is to provide a manufacturing method thereof and a hollow fiber membrane module.

In order to achieve the above object, the present invention includes the following configurations.
(1) In succession to the spinning step of the porous hollow fiber membrane, the porous hollow fiber is repeatedly immersed and drained in a 70 to 90% by weight glycerin aqueous solution or glycerin derivative aqueous solution. The water filled in the hollow part and the pore part of the membrane is replaced with an aqueous glycerin solution or an aqueous glycerin derivative solution, followed by drying and filling with a porous hollow fiber membrane adjusted to a moisture content of 3 to 12% by weight. a hollow fiber membrane module, the hollow fiber membrane module, characterized in that it is stored at a temperature 60 ° C. or less, humidity of 20% or less.
(2) When the hollow fiber membrane module is primed, the ratio of UFR (A), which is water permeable 5 minutes after treatment, to UFR (B), which is water permeability 30 minutes after treatment (UFR (A ) / UFR (B)) is 90% or more, the hollow fiber membrane module according to (1).

  According to the present invention, a hollow fiber filled with a conventional gas, such as air or nitrogen gas, or a hydrophobic fluid, such as liquid paraffin, by filling not only the inside of the pores but also the hollow portion with a hydrophilizing agent. Compared to membranes, it can suppress partial hydrophobicity of the surface of the hollow fiber membrane, and therefore, immediately after priming with an aqueous fluid, even after long-term storage and drying in a high temperature and / or low humidity environment Desired performance can be exhibited. Because of these advantages, the porous hollow fiber membrane and the hollow fiber membrane module of the present invention can be suitably used for aqueous fluid treatment such as water treatment, blood treatment, and food.

  In addition to the membrane wall portion (inside the pores) of the porous hollow fiber membrane, filling the hollow portion with a hydrophilizing agent can also suppress partial hydrophobicity of the porous membrane. Even after long-term storage and drying in a high-temperature and / or low-humidity environment, desired performance can be quickly exhibited immediately after priming with an aqueous fluid.

Hereinafter, embodiments of the present invention will be described in detail.
In the present invention, it is preferable that the hollow portion is filled with a hydrophilizing agent in addition to the inside of the pores of the porous hollow fiber membrane. As a result of the study, it was found that the above problems can be solved by filling the hollow portion with a hydrophilizing agent not only inside the pores of the porous hollow fiber membrane but also storing the porous hollow fiber membrane or manufacturing a module. It was done.

  In the present invention, it is preferable to use glycerin or a glycerin derivative as the hydrophilizing agent that fills the pores and the hollow part of the porous hollow fiber membrane. For example, in a hollow fiber membrane for blood purification, glycerin has been conventionally used as a pore size retaining agent, and polyvinylpyrrolidone, polyethylene glycol, or the like has been used as a membrane hydrophilizing agent. When glycerin is filled into the pores of the membrane, the glycerin is a highly viscous liquid, and the pore diameter is sufficiently small so that there is almost no falling out of the pores in a relatively short time. It can be easily removed by a cleaning operation such as priming. It is also preferably used from the viewpoint of safety. On the other hand, polyvinylpyrrolidone and polyethylene glycol are preferably used as a hydrophilizing agent, but have disadvantages such as a problem of elution into blood and inability to use as a pore diameter retaining agent.

  The present inventor has filled glycerin or a glycerin derivative, which has been conventionally used as a pore diameter retaining agent, not only in the pores but also in the hollow part, so that the hollow fiber membrane module can be used during the manufacturing process and storage of the hollow fiber membrane. It was considered that the hydrophobicity of the hollow fiber membrane could be suppressed even during the production. However, although it is possible to easily fill the hollow part with glycerin, it is necessary to consider that the filled glycerin does not drop and leak from the hollow part.

In the present invention, in order to prevent the hydrophilic agent (such as glycerin) filled in the hollow part from dropping off or leaking, it is necessary to optimize the structure of the hollow fiber membrane and to consider it during storage.
The structure of the hollow fiber membrane preferably has at least a dense layer on the inner surface side. It is preferable to have a dense layer on the outer surface side because a double barrier can be formed. Moreover, it is more preferable that the thickness, the pore diameter, and the porosity of the dense layer are in a specific range. The thickness of the dense layer may be about 0.1 to 5 μm although it depends on the thickness of the hollow fiber membrane. If the dense layer is too thin, defects are likely to be exposed and may lead to leakage of the hydrophilizing agent, so 0.2 μm or more is more preferable, and 0.3 μm or more is more preferable. The pore diameter of the dense layer is preferably 1 to 50 nm, more preferably 2 to 35 nm, and even more preferably 3 to 20 nm. When the pore diameter of the dense layer is within the above range, it is possible to effectively prevent a hydrophilizing agent such as glycerin from leaking out of the membrane through the pores.

  The present invention can be applied to porous hollow fiber membranes used for various applications, and in particular, application to blood purification hollow fiber membranes is more preferable. Therefore, the inner diameter of the porous hollow fiber membrane is preferably 150 μm or more and 300 μm or less. If the inner diameter of the hollow fiber membrane is too small, the blood flow linear velocity increases, and the blood cell component may be damaged. If the hollow fiber membrane is too large in diameter, the blood shear rate and pressure loss will not increase, the filtration effect contributing to the permeation of medium high molecular weight substances will be reduced, and a module (blood purifier) to compensate for the lack of membrane performance There is a possibility that the convenience of use may be impaired, such as having to increase the size. Therefore, the inner diameter of the hollow fiber membrane is more preferably 160 μm or more and 280 μm or less, and further preferably 170 μm or more and 260 μm or less.

  In the present invention, the thickness of the hollow fiber membrane is preferably 10 μm or more and less than 50 μm. If the thickness of the hollow fiber membrane is too thin, the permeation performance is improved, but it may be difficult to maintain the required strength. On the other hand, if the film thickness is too large, the permeation resistance of the substance increases, and the permeability of the removed substance may be insufficient. In addition, there is a possibility that the convenience of use may be impaired because the size of the module needs to be increased. Furthermore, if the film thickness is too thick, the workability and efficiency when the hollow forming agent is replaced with the hydrophilizing agent solution may be reduced in the spinning film forming step described later. Therefore, the film thickness of the hollow fiber membrane is more preferably 13 μm or more and 40 μm or less, and further preferably 16 μm or more and 30 μm or less.

  In order to obtain the hollow fiber membrane of the present invention, a spinning solid solution composed of a polymer, a solvent, a non-solvent, and a core liquid (hollow forming material) is used as a coagulable liquid and simultaneously discharged from a nozzle. Then, the hollow fiber membrane shape is fixed. Excess solvent and non-solvent are removed from the obtained hollow fiber membrane in a washing bath, and the membrane pore retainer is impregnated into the hollow portion and the inside of the pore, and then dried and wound up.

  In the present invention, it is preferable to mainly use a cellulose acetate polymer as a material (polymer) constituting the hollow fiber membrane. Cellulose acetate-based polymers include cellulose diacetate and cellulose triacetate capped to some extent from the viewpoint of blood compatibility, such as the balance between hydrophobicity and hydrophilicity, suppression of complement activity, and good blood return without blood clotting. Is easily available and is particularly preferable.

  In order to balance the performance of the hollow fiber membrane and the strength of the membrane, the pore diameter and thickness of the dense layer, and the porosity, the cellulose acetate polymer concentration in the spinning dope should be set to 16 wt% or more and 25 wt% or less. Preferably, it is more preferably 17% by weight or more and 23% by weight or less.

  In the present invention, it is preferable to use N-methylpyrrolidone (hereinafter sometimes referred to as NMP), dimethylformamide, dimethylacetamide, dimethylsulfoxide and the like as the solvent for the cellulose acetate polymer. These solvents have good compatibility with water and exhibit coagulability with respect to the cellulose acetate polymer. Non-solvents include ethylene glycol, triethylene glycol (hereinafter sometimes referred to as TEG), polyethylene glycol, glycerin, propylene glycol, alcohols, and the like.

  In the present invention, as the core liquid, an aqueous solution composed of the above-mentioned solvent, non-solvent and water can be generally used, but may further contain a swelling agent and other additives. The hollow fiber membrane of the present invention is not only filled with pores but also filled with a hydrophilizing agent in the hollow part. That is, it is preferable from the viewpoint of workability and cost that the hydrophilizing agent is used as the non-solvent used in the spinning dope and the coagulating solution, but the present invention is not limited to this. You only have to set it.

  When a cellulose acetate polymer is used as a raw material, if the water content of the core liquid is too low, the coagulation property of the polymer is lowered. Therefore, even if the polymer concentration in the spinning stock solution is increased, the formation of a dense layer and the porosity are not uniform. It is easy to become. Therefore, the water content in the core liquid is preferably 10% by mass or more. 30 mass% or more is more preferable, 50 mass% or more is further more preferable, 70 mass% or more is further more preferable, It is especially preferable to use water alone. On the other hand, if the water content of the core liquid becomes too high, the spinning dope discharged from the nozzle is rapidly solidified, so that the spinnability is deteriorated and yarn breakage or deformation of the hollow fiber membrane occurs. Is likely to occur. Here, in the present invention, a cellulose acetate polymer having a lower viscosity than a conventionally known cellulose acetate polymer is used, and the reason is not clear. However, even if the water content of the core liquid is increased, the yarn breakage is lost. It was found that good spinning stability can be obtained without occurrence of.

  Factors that determine the structure of the hollow fiber membrane of the present invention are affected by the polymer concentration in the spinning dope, the nozzle temperature, etc. In addition, the air until the spinning dope discharged from the nozzle is immersed in the coagulation bath. It is also affected by the length (time) of the running section. In the present invention, it is preferable that the length of the aerial traveling portion is 10 mm or more and 600 mm or less. Moreover, it is preferable to block the aerial traveling part from the outside air and set the interior to 0 ° C. or more and 50 ° C. or less. By setting the length and temperature of the aerial traveling portion within the above ranges, the membrane structure in the vicinity of the outer surface of the hollow fiber membrane can keep a good balance between the leakage preventing property of the hydrophilizing agent and the membrane performance. On the other hand, on the inner surface side of the spinning dope, it is possible to complete the coagulation of the polymer with the core solution and form a dense layer before being affected by the solvent removal from the outer surface side.

In order to improve the stability of the spinning film formation, the length of the aerial traveling part is more preferably 10 mm or more and 300 mm or less, and 10 mm or more and 150 mm or less is more preferable to offset the influence of the spinning stock discharge from the spinneret. . The temperature of the aerial traveling section is preferably 3 ° C. or higher and 45 ° C. or lower in terms of easy control, and more preferably 5 ° C. or higher and 40 ° C. or lower in order to suppress the leakage of useful proteins in terms of performance.
The appropriate range of the length and temperature of the aerial traveling section varies depending on the nozzle draft and spinning speed. The scope of the present invention assumes that the nozzle draft is about 1 to 5 and the spinning speed is 30 to 90 m / min. doing.

  In the present invention, in order to obtain an appropriate hollow fiber membrane structure, it is also an important requirement to optimize the conditions of the coagulation bath. In order to reduce the void ratio and pore diameter on the outer surface side, it is effective to lower the solvent concentration in the coagulation bath and lower the temperature. The solvent concentration in the coagulation bath is preferably 50% by weight to 80% by weight, and the coagulation bath temperature is preferably 20 ° C. or more and 70 ° C. or less. From the viewpoint of securing the hollow fiber membrane from the coagulation bath and the ease of temperature control of the aerial running part, the solvent concentration should be 55 to 77% by weight, and the coagulation bath temperature should be 30 to 50 ° C. More preferably, the solvent concentration is 60 wt% or more and 75 wt% or less, and the coagulation bath temperature is 35 ° C. or more and 45 ° C. or less.

  The hollow fiber membrane squeezed out from the coagulation bath is subsequently washed in a water washing bath to remove excess solvent and non-solvent. In order to perform cleaning in a short time, it is better to raise the temperature of the washing bath as much as possible. However, if the temperature is too high, the film constituent material may be deteriorated or the film shape or the film structure may be defective. Therefore, the washing is preferably performed at about 30 to 90 ° C, more preferably 40 to 90 ° C, 50-85 degreeC is further more preferable.

The hollow fiber membrane that has undergone the water washing step is then transferred to the step of filling the inside of the pores and the hollow portion with the hydrophilizing agent. In the present invention, by repeatedly immersing the porous hollow fiber membrane in the glycerin aqueous solution and draining it, the glycerin aqueous solution as the hydrophilizing agent is filled into the pores, and at the same time the hollow hollow fiber membrane is hollow. The hollow forming agent filled in the part is replaced with an aqueous glycerin solution. Here, the concentration of glycerin is preferably 70 to 95% by weight. If the glycerin concentration is too low, the pore diameter may be reduced and the hollow fiber membrane shape may be deformed (crushed or flattened) due to moisture evaporation in the subsequent hollow fiber membrane drying step. On the other hand, if the glycerin concentration is too high, the fluidity is lowered and filling and replacement may be insufficient. Therefore, the glycerin concentration is more preferably 75 to 93% by weight, and further preferably 80 to 90% by weight.
The temperature of the glycerin aqueous solution depends on the glycerin concentration, but is preferably about 80 to 95 ° C. within the above range. If it is such a temperature range, the fluidity | liquidity of glycerin aqueous solution will be ensured and it is preferable at the surface of a filling property or substitution property.
In the present invention, the time and frequency of immersing and draining in the glycerin aqueous solution are related to the inner diameter, the film thickness, and the membrane structure of the hollow fiber membrane, and thus cannot be said unconditionally. If it is about ˜50 μm, it can be said that it is sufficient to perform immersion and liquid removal for about 3 to 10 seconds each, and about 3 to 10 times for immersion and liquid removal as one step.

  The hollow fiber membrane in which the glycerin aqueous solution is filled in the pores and in the hollow part is wound around a bobbin in a cheese shape through a drying process. Here, the moisture content of the hollow fiber membrane after drying is preferably adjusted to 13% by weight or less. If the moisture content is too high, moisture in the atmosphere is absorbed when the hollow fiber membrane is stored, causing leakage and dropping. In addition, when a hollow fiber membrane module is produced, a resin such as urethane used for sealing an end of the hollow fiber membrane reacts with water and foams, or a by-product such as a urethane oligomer occurs. There is. On the other hand, if the moisture content is too low, the hygroscopicity is increased, so that it is necessary to control the storage conditions severely. Therefore, the moisture content of the hollow fiber membrane after drying is more preferably 3 to 12% by weight, further preferably 4 to 11% by weight, and still more preferably 5 to 10% by weight.

  A plurality of the obtained hollow fiber membranes are bundled, inserted into the housing case, and a urethane adhesive is used when the ends are bonded with resin. The urethane adhesive is not particularly limited as long as it uses a polyol as a main agent and a polyisocyanate as a curing agent and the curing reaction proceeds by a urethane bond, and the polyisocyanate component is aromatic or aliphatic. Any of these can be used. It is preferable to appropriately select the polyol component and the polyisocyanate component in consideration of the handling properties of the resin and the characteristics required depending on the application.

  The porous hollow fiber membrane of the present invention and the module containing the porous hollow fiber membrane are preferably stored at a temperature of about 60 ° C. or less and a humidity of about 20% or less. If the temperature is too high or the humidity is too high, even if the moisture content of the hollow fiber membrane is adjusted to the above-described range, moisture absorption during storage, and consequently the fluidity of the hydrophilizing agent due to moisture absorption increases, The hydrophilizing agent may fall off and leak from the inside of the pores. If the hydrophilizing agent falls off and leaks, it may lead to shrinkage of the pores or deformation of the hollow fiber membrane shape, which may cause performance degradation or quality degradation.

  The porous hollow fiber membrane obtained by the method of the present invention is excellent in priming property (rewetting property) at the time of use because it particularly takes measures for suppressing the hydrophobization of the inner surface. Specifically, ratio of water permeability (UFR (A)) 5 minutes after priming to water permeability (UFR (B)) 30 minutes after priming (UFR (A) / UFR (B)) Is preferably 90% or more. For example, when the porous hollow fiber membrane is used for blood purification, the time from priming treatment to clinical use in a dialysis facility is about 5 to 10 minutes at the shortest. In such a facility, it is necessary to express the desired performance immediately after priming. Therefore, UFR (A) / UFR (B) is more preferably 93% or more, and still more preferably 96% or more.

  Conventionally, hydrophilic components such as polyvinylpyrrolidone (PVP) and polyethylene glycol have been added to improve (improve) the hydrophilicity of hollow fiber membranes, as typified by porous hollow fiber membranes made of polysulfone polymers. Hollow fiber membranes are known. However, since PVP is a high molecular weight hydrophilic material, it easily dissolves into blood and accumulates in the living body because of its high molecular weight. Since the hollow fiber membrane of the present invention uses glycerin or a glycerin derivative as a hydrophilizing agent, even when used for blood purification or the like, it is quickly washed away in the priming treatment, and there is no fear of adverse effects on the living body.

  Hereinafter, preferred embodiments of the present invention will be described with reference to Examples. However, the present invention is not limited to this.

(Measurement of film thickness of hollow fiber membrane)
The cross section of the hollow fiber membrane is projected with a projector with a magnification of 200 times, and the inside diameter (A) and the outside diameter (B) of the hollow fiber having the maximum, minimum, and medium sizes are measured in each field of view. The film thickness of
Film thickness = (B−A) / 2
Calculate the average of 15 hollow fiber membranes per field of view.

(Pore diameter on the inner surface of the hollow fiber membrane)
The inner surface of the hollow fiber membrane is observed with an electron microscope with a magnification of 100,000 times, and a photograph (SEM photograph) is taken. The image is processed with image analysis software to determine the pore diameter on the inner surface of the hollow fiber membrane. The image analysis software is measured using, for example, Image Pro Plus (Media Cybernetics, Inc.). The emphasis / filtering operation is performed on the captured image so that the hole and the blockage are identified. Thereafter, the pore diameter of the pores is measured, and when the lower polymer chain can be seen inside the pores, the pores are combined and regarded as one hole. This is carried out 10 views and the average is obtained. Set the scale as the initial operation.

(Measurement of dense layer thickness)
The thickness of the dense layer of the hollow fiber membrane in the present invention was determined as follows.
The cross section of the hollow fiber membrane was observed with a scanning electron microscope (SEM) at a magnification of 3000 times, a portion where no pores or voids were clearly observed was defined as a dense layer, and the thickness of the portion was measured.

(Priming of hollow fiber membrane modules)
The hollow fiber membrane module is placed vertically, ion exchange is performed, water is started to flow to the hollow part side at a flow rate of 100 ml / min, air bubbles are sufficiently removed, and after 1000 ml or more of ion exchange water has been poured, the hollow fiber is discharged from the hollow part outlet side Connect the circuit to the outer part and let it flow for 5 minutes.

(Measurement of water permeability of hollow fiber membrane)
The water permeability is measured according to the following procedure.
A hollow fiber membrane module filled with 3000 to 20000 hollow fiber membranes is produced. The hollow fiber membrane area used for the calculation is based on the hollow fiber inner diameter (ID), and the effective membrane area is calculated from the effective length (L) excluding the bonded portion. Pure water is passed through the hollow fiber membrane in advance (hollow part) and the hollow fiber membrane outside (inside the module) in this order to remove bubbles. After adjusting the pure water filled in the module and the inside to 37 ° C., pressure is applied by pure water at 37 ° C. from the module inlet leading to the inside (hollow part) of the hollow fiber membrane, the pressure difference between the inside and outside of the membrane, That is, a transmembrane pressure difference (P) is generated, and the amount (W) of pure water that flows out of the membrane through the membrane in one minute is measured. Measure W for one minute at four different P points, plot P and W on two-dimensional coordinates, and determine the slopes of these approximate lines as numerical values. Next, the water permeability (UFR, ml / (m ² · h · mmHg)) of the hollow fiber membrane is calculated by the following formula. UFR = W (ml / min) × 60 (min / h) ÷ A (m ² ) ÷ P (mmHg) where effective membrane area A (m ² ) = ID (μm) × 10 ⁻⁶ × π × L (M) x number of hollow fibers.

(Water content of hollow fiber membrane)
The moisture content of the porous hollow fiber membrane in the present invention was calculated by the following formula.
Moisture percentage% = 100 × (Ww−Wd) / Wd
Here, Ww is the weight (g) of the hollow fiber membrane before drying, and Wd is the weight (g) of the hollow fiber membrane after being dried in a dry heat oven at 120 ° C. for 2 hours or more (after absolutely dry).

Example 1
As the spinning dope, cellulose triacetate (Daicel Chemical Industries, Ltd.) 19.0% by weight, N-methyl-2-pyrrolidone (Mitsubishi Chemical Co., Ltd.) 68.9% by weight, triethylene glycol (Mitsui Chemicals) 12.1 The wt% was mixed and dissolved at 180 ° C. This was degassed by a known method, passed through a sintered filter, and discharged vertically downward from the outer tube of a spinneret having a double tube structure. At the same time, reverse osmosis treated water (RO water) was supplied to the inner tube as a core liquid. The hollow fiber discharged from the spinneret passes through a 13 mm idle running part, passes through a coagulation bath, a water washing bath, a glycerin bath, and is dried online, and then is turned into a cheese on a bobbin at a winding speed of 60 m / min by a winder. Winded up. The composition of the coagulation bath was set to NMP / TEG / water = 59.5 / 10.5 / 30.0, and the temperature was set to 45 ° C. The glycerin concentration in the glycerin bath was 88.0% by weight, and the temperature was set at 92 ° C. Moreover, the hollow forming agent filled in the hollow portion was completely replaced with the glycerin aqueous solution by repeating the dipping and draining three times. The inner diameter and the film thickness of the hollow fiber membrane after drying were 203 μm and 20 μm, respectively. The moisture content of the hollow fiber membrane after drying was 12% by weight. 10,200 hollow fiber membranes thus obtained were converged, cut and inserted into a housing case. The end part was bonded using a urethane adhesive, and the produced hollow fiber membrane module was allowed to stand for 12 hours at 60 ° C. and a humidity of 20% or less, and then subjected to priming with ion-exchanged water, 5 minutes after priming, Water permeability was measured after 30 minutes, 60 minutes, 180 minutes and 12 hours.

(Example 2)
As the spinning dope, cellulose triacetate (manufactured by Daicel Chemical Industries) 20.0% by weight, N-methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical) 64.0% by weight, triethylene glycol (manufactured by Mitsui Chemicals) 16.0% The wt% was mixed and dissolved at 180 ° C. This was degassed by a known method, passed through a sintered filter, and discharged vertically downward from the outer tube of a spinneret having a double tube structure. At the same time, RO water was supplied to the inner tube as a core liquid. The hollow fiber discharged from the spinneret passed through an empty running portion of 25 mm, passed through a coagulation bath, a water washing bath, and a glycerin bath, dried on-line, and then wound around a bobbin by a winder at a winding speed of 60 m / min. . The composition of the coagulation bath was set to NMP / TEG / water = 56.0 / 14.0 / 30.0, and the temperature was set to 55 ° C. The glycerin concentration in the glycerin bath was 78.0 wt%, and the temperature was set at 80 ° C. Moreover, the hollow forming agent filled in the hollow portion was completely replaced with the glycerin aqueous solution by repeating the dipping and draining three times. The hollow fiber membranes after drying had an inner diameter and a film thickness of 198 μm and 22 μm, respectively. The moisture content of the hollow fiber membrane after drying was 6% by weight. 10,200 hollow fiber membranes thus obtained were converged, cut and inserted into a housing case. The end part was bonded using a urethane adhesive, and the produced hollow fiber membrane module was allowed to stand for 12 hours at 60 ° C. and a humidity of 20% or less, and then subjected to priming with ion-exchanged water, 5 minutes after priming, Water permeability was measured after 30 minutes, 60 minutes, 180 minutes and 12 hours.

(Comparative Example 1)
A hollow fiber membrane was obtained in the same manner as in Example 1. The obtained hollow fiber membrane was allowed to stand in an environment of a temperature of 60 ° C. and a humidity of 80% for 24 hours, and then the hollow fiber membrane was inserted into a housing case and the ends were bonded using a urethane-based adhesive. When the adhesive cured part was observed, foaming of the adhesive was confirmed, and there was a problem in quality. Moreover, the occurrence of leaks that may be caused by poor adhesion due to foaming was also observed.

(Comparative Example 2)
As the spinning dope, cellulose triacetate (Daicel Chemical Industries, Ltd.) 18.0% by weight, N-methyl-2-pyrrolidone (Mitsubishi Chemical Co., Ltd.) 57.4% by weight, triethylene glycol (Mitsui Chemicals, Inc.) 24.6% What was mixed and dissolved by weight at 180 ° C. was used. This was passed through a sintered filter and then discharged vertically downward from a spinneret having a double tube structure. At the same time, liquid paraffin was supplied to the inner tube as a core liquid to form a hollow fiber membrane. The hollow fiber membrane passed through a 60 mm steam atmosphere, passed through a coagulation bath, a water washing bath, and a glycerin bath, dried on-line, and then wound on a bobbin at a winding speed of 75 m / min. The glycerin concentration was 65.0% by weight, and the bath temperature was set to 85 ° C. In this comparative example, liquid paraffin, which is a hydrophobic liquid, is used as the hollow forming material (core liquid), and thus the hollow portion of the hollow fiber membrane was not filled with glycerin. The hollow fiber membrane after drying had an inner diameter and a thickness of 200 μm and 17 μm, respectively. The moisture content of the hollow fiber membrane after drying was 12% by weight. 10,200 hollow fiber membranes thus obtained were converged, cut and inserted into a housing case. The end part was bonded using a urethane adhesive, and the produced hollow fiber membrane module was allowed to stand for 12 hours at 60 ° C. and a humidity of 20% or less, and then subjected to priming with ion-exchanged water, 5 minutes after priming, Water permeability was measured after 30 minutes, 60 minutes, 180 minutes and 12 hours.

  The results of Examples and Comparative Examples are shown together in Table 1.

  By comparing the above-mentioned Examples and Comparative Examples, the hollow fiber membrane and the hollow fiber membrane module in which the hollow portion and pores of the porous hollow fiber membrane of the present invention are filled with a hydrophilizing agent Since consideration is given to the surface hydrophobization suppression, it can be seen that the wettability in the standard priming treatment is excellent, that is, the water permeability is excellent.

Since the porous hollow fiber membrane of the present invention is filled with a hydrophilizing agent not only in the pores but also in the hollow portion, it can be stored in a hollow fiber membrane or in a module state for a long period of time or in a high temperature and low humidity environment. In addition, the hydrophobicity of the hollow fiber membrane can be effectively suppressed, and the desired performance is excellent in various storage periods, storage states, and various uses.

Claims (2)

In succession to the spinning step of the porous hollow fiber membrane, the porous hollow fiber membrane is hollowed by repeatedly immersing and draining the porous hollow fiber membrane in a 70 to 90% by weight glycerin aqueous solution or glycerin derivative aqueous solution. The hollow fiber membrane is formed by replacing the water filled in the parts and pores with a glycerin aqueous solution or a glycerin derivative aqueous solution, followed by drying and filling a porous hollow fiber membrane with a moisture content adjusted to 3 to 12% by weight. A hollow fiber membrane module which is a module and is stored at a temperature of 60 ° C. or less and a humidity of 20% or less. When the hollow fiber membrane module is primed, the ratio of UFR (A), which is permeable 5 minutes after treatment, to UFR (B), which is permeable 30 minutes after treatment (UFR (A) / UFR The hollow fiber membrane module according to claim 1, wherein (B)) is 90% or more.